This invention relates to off-gas recombiners for nuclear power plants.
In a steam turbine-generator nuclear power plant, turbine exhaust is fed to a main condenser where water vapor is condensed and returned to a nuclear reactor for reheating. Free oxygen, hydrogen and various radioactive gases are in solution with the water vapor exhausted from the turbine. "Off-gas" is that portion of the steam turbine exhaust which is not condensed and returned to the system by the main condenser.
An off-gas recombiner functions to recombine the free oxygen and hydrogen into water vapor and then condensed water, while feeding other non-condensable off-gases to other off-gas treatment apparatus employed in the power plant. To recombine the free oxygen and hydrogen, such a recombiner heats the free elements, places the free elements in contact with a suitable catalyst effecting their recombination into water vapor, and cools this resulting water vapor condensing it into a liquid.
Prior art recombiners have taken the form of a serial connection of heaters, catalysts, and condensers in fluid communication with each other through complex piping networks. These recombiners have various disadvantages associated with them. Serial connections of the recombiner components are disadvantageous in that high manufacturing costs are encountered in fabricating separate vessels for each component and providing suitable piping for the fluid communication between such individual components. In addition, such complex networks of piping results in high pressure drops contributing to a high operating cost of the off-gas recombiner. Such high manufacturing costs encountered in the provision of a plurality of vessels and suitable piping therebetween are eliminated in this invention. High operating costs associated with pressure drops within such piping networks are also eliminated with this invention.